Bug 128104

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Description of problem:
Lock files created under /var/lock are erroneously removed under
certain circumstances.

Lock files should be removed by a process trying to acquire the lock,
if the locking process is not alive any more. However, the test
against the existing process id is broken, resulting in an abnormal
behavior.

Particularly, the kill() system call is used to determine whether a
process id (pid) still exists or not. The problem is that the only
check is made against the return value, which is expected to be 0 if
kill() succeeds and -1 otherwise. However, a failure of kill() does
not necessarily mean that the pid does not exist; it may also mean
that the calling uid doesn't have permission to kill() the specified pid.

I fixed the bug, and a patch is available at:
http://radu.rendec.ines.ro/lockdev-1.0.1-pidexists.patch

Please consider checking the patch and including it in the official
distribution.

I also made a patch against the package spec file, which you might
find useful. It's available at:
http://radu.rendec.ines.ro/lockdev-specfile-pidexists.patch

Should you have any questions or comments regarding this issue, please
do not hesitate to contact me.

Version-Release number of selected component (if applicable):
lockdev-1.0.1-1.3

How reproducible:
Always

Steps to Reproduce:
1.Lock a device as root
2.Try to lock the same device as unprivileged user

    

Actual Results:  The lockfiles created at step 1 are replaced by new
lockfiles. The process running as unprivileged user thinks the process
running as root is dead, because it can't be killed.

Expected Results:  The process running as unprivileged user should not
have been able to acquire the lock.

Additional info: